[Patch] My proposal for _Alloc_traits-free rope

[Benjamin Kosnik]

>Suggest we deprecate the whole thing for 3.4 (along with slist?  hmmm)
>and kill it in 3.5.

Well, the point is to not rework for the new allocator model. Paolo has
done rope, but who knows. Paolo, I think that you've given Matt more
than enough time to respond to this: if he hasn't responded by tonight,
please check in the rope bits you've done.

Right now, rope, slist, and bvector need to be reworked. 

We need to finish the allocator transition ASAP.

-benjamin